1. 上下标 # 注意y轴标签文字 library(ggplot2) ggplot(mtcars, aes(mpg, cyl))+geom_point()+ylab(label =bquote(O[3]~(ug / m^3))) 2. 希腊字母,如alpha ggplot(mtcars, aes(mpg, cyl))+geom_point()+ylab(label =bquote(O[3]~(ug / m^3)))+ggtitle(expression(alpha)) = end =